Hi How are you multiplying it to 1 GHz and checking it?
I've seen multipliers that have issues beyond about -130 at 100 Hz. It's not common, but it can happen. ------------------ The supply provided by TAPR is a pretty basic unit. It would not surprise me if some were better than others. They also may work better on US mains voltage than they do on international voltages. I would rig up another supply and see what happens. That would at least rule out the supply as an issue. In a previous post the idea of putting a 7805 and 7812 regulator on the TBolt came up. If you have +14 available that seems like the best thing to try. Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Christophe Huygens Sent: Tuesday, March 09, 2010 7:50 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Realistic Tbolt phase noise This is with the power supply as provided by TAPR so should be ok. Xtof. On 09/03/10 13:44, Bob Camp wrote: > Hi > > Power supply noise would be the first thought. > > Next up would be grounding inside the Thunderbolt (card to case, connectors to case). > > Bob > > > On Mar 9, 2010, at 7:32 AM, Christophe Huygens wrote: > > >> Hi, >> >> I noticed several vendors on Ebay have the t-bolt on sale. >> >> However, the once showing their own PN plots seem to get only >> -115, -120 dBc/Hz at 100Hz. Yet, >> http://www.leapsecond.com/pages/tbolt/noise.htm seems >> to have mucht better results: up to -150 depending on >> power supply. >> >> By multiplying to 1GHz I also seem to be getting something >> like -75 or - 80 rather than -110. >> >> Any thoughts? >> >> Christophe >> on4iy >> >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
